Surface Modeling in LCAO Calculations of Metal Oxides

Abstract

n this chapter the capacity of LCAO methods in surface modeling is illustrated with numerous results of recent LCAO calculations. To model the electronic structure of surface states of crystals, three basic approaches are used: the cluster, slab (single and periodic), and semi-infinite crystal models. In the single-slab model, a crystal with a surface is approximated by a slab of finite thickness. The symmetry group of this model (diperiodic or layer group) allows the existence of symmetry operations that move the atoms out of the plane of the layer but bring them into positions occupied by other atoms of the slab. The results of the first-principles calculations of TiO2, SnO2, SrTiO3, SrZrO3, and LaMnO3 surfaces are discussed.